tag:blogger.com,1999:blog-4071831961528467035.comments2023-09-23T06:07:13.771-07:00Prehistoric PubAnonymoushttp://www.blogger.com/profile/11914892485880621750noreply@blogger.comBlogger24125tag:blogger.com,1999:blog-4071831961528467035.post-71489118419621571462017-05-22T16:59:54.259-07:002017-05-22T16:59:54.259-07:00Thanks for the blog post Rob!Thanks for the blog post Rob!MADOhttps://www.blogger.com/profile/02561474109519414636noreply@blogger.comtag:blogger.com,1999:blog-4071831961528467035.post-27985207876227337222017-05-21T05:05:00.949-07:002017-05-21T05:05:00.949-07:00Losing weight is actually easy if you get the righ...Losing weight is actually easy if you get the right support or guide , i was searching online and came upon this website and found out that many had success in losing weight, i am also seeing wonderful results, here is that site, hope it will help those who really want to lose weight ,<br /><br /><a href="https://healthyyfatloss.blogspot.ca" rel="nofollow">https://healthyyfatloss.blogspot.com</a><br />Anonymoushttps://www.blogger.com/profile/08420625062845949635noreply@blogger.comtag:blogger.com,1999:blog-4071831961528467035.post-65754888386232125982017-04-12T16:32:45.811-07:002017-04-12T16:32:45.811-07:00What a tremendous resource. Thanks for all your ef...What a tremendous resource. Thanks for all your efforts. Looking forward to seeing you the annual meeting.Williamhttps://www.blogger.com/profile/08577587798712060168noreply@blogger.comtag:blogger.com,1999:blog-4071831961528467035.post-87313876314327429152017-01-03T16:01:55.430-08:002017-01-03T16:01:55.430-08:00Thanks!Thanks!Anonymoushttps://www.blogger.com/profile/11914892485880621750noreply@blogger.comtag:blogger.com,1999:blog-4071831961528467035.post-35012988401698295902017-01-03T14:31:14.703-08:002017-01-03T14:31:14.703-08:00Congratulations, Rob. You made a difference.Congratulations, Rob. You made a difference.Anonymoushttps://www.blogger.com/profile/17533817798068275777noreply@blogger.comtag:blogger.com,1999:blog-4071831961528467035.post-56511596774343478642016-12-30T23:55:26.348-08:002016-12-30T23:55:26.348-08:00Hi Robert, to your points...
It's not circula...Hi Robert, to your points...<br /><br />It's not circular to argue that given 1. the only LJ taxon that's been shown to have fluted anterior teeth is Ceratosaurus, and 2. I found isolated fluted anterior teeth from the LJ, thus 3. these are most likely Ceratosaurus teeth. It would only be circular if we defined Ceratosaurus as the animal that all fluted anterior LJ teeth belonged to, so that if we found a Morrison croc with those teeth, we concluded the croc must be Ceratosaurus. Similarly, it would only be self-reinforcing if we counted every isolated tooth thus referred to Ceratosaurus as further confirming evidence all such teeth belonged to Ceratosaurus. But I'm not arguing in that way. I think the fluted dentisulcatus specimen added to the lack of fluted examples in other Morrison taxa or their relatives is good enough for our provisional need.<br /><br />I don't think being part of a formal diagnosis matters, since these vary highly in quality and are often nullified by close relatives that weren't considered. How many formal diagnoses of Ceratosaurus took into account Genyodectes, Ostafrikaasaurus and Eoabelisaurus (an abelisaurid in some of Wang et al.'s 2016 trees; did you know it had osteoderms too?)?<br /><br />You claim characters used in diagnoses are bad when they are "untested" and "easy-to-evolve", but what do either of these really mean, and just how many characters used in e.g. Mesozoic theropod diagnoses have been tested or can be evaluated for ease of evolution? Is the latter just a short-hand for the amount of times they've evolved convergently in archosaurs/reptiles/tetrapods/vertebrates?<br /><br />The premaxillary teeth of Torvosaurus are unknown, but Duriavenator and Dubreuillosaurus lack fluting in theirs. At least the former is always found to be a megalosaurid, and so closer to Torvosaurus than to spinosaurids. You could correctly argue that megalosauroid topologies aren't strongly supported at the moment and that Duriavenator has basically only been tested in variants of Benson's matrix, but this just goes back to my point about there always being caveats in our field.Mickey Mortimerhttps://www.blogger.com/profile/08831823442911513851noreply@blogger.comtag:blogger.com,1999:blog-4071831961528467035.post-79479858467927073572016-12-30T06:40:56.207-08:002016-12-30T06:40:56.207-08:00A secondary point; you said, "It would be dif...A secondary point; you said, "It would be different if a relative of a Morrison taxon had the character, and the state was unknown for the Morrison taxon. Then you might say that Morrison taxon could also be a contender for owning the isolated fluted teeth, but that's not the case for Ceratosaurus' contemporaries AFAIK."<br />While not terribly close relatives, spinosaurids are megalosaurs and the premaxillary teeth of Torvosaurus are unknown.Anonymoushttps://www.blogger.com/profile/11914892485880621750noreply@blogger.comtag:blogger.com,1999:blog-4071831961528467035.post-28506067047244403722016-12-30T06:38:40.059-08:002016-12-30T06:38:40.059-08:00Hi Mickey,
Thanks for taking the time to read thr...Hi Mickey,<br /><br />Thanks for taking the time to read through things. I definitely value your input and appreciate your perspective here.<br /><br />I wasn't bringing up fluted teeth in phytosaurs to suggest that perhaps some of these Morrison fluted teeth were bizzaro Late Jurassic phytosaurs, clearly. The point is that this is an easy-to-evolve adaptation that has appeared in multiple lineages throughout the last 220 million years, including in unrelated but coeval taxa (such as phytosaurs and metoposaurs). I think it is kind of circular to say that "These fluted teeth are from the Late Jurassic so they must be Ceratosaurus because it is the only Late Jurassic animal with fluted teeth," even when we don't know that to be true. It becomes self-reinforcing, doesn't it?<br />And before you point it out, that doesn't take into account your other point; we don't know the variation in other taxa (some very poorly known) but that it shouldn't prevent us from making assignments, "if we held this standard to every taxon, we wouldn't get far at all with diagnoses."<br />I guess my concern boils down to two things: 1) This isn't actually a character that has been formally diagnosed for Ceratosaurus itself, just something that we all have sort of agreed on but haven't actually tested. 2) Confidently assigning specimens to taxa (and erecting new taxa) because of untested (but assumed) characters in teeth created a lot of the taxonomic mess in Triassic dental studies. Hopefully we can avoid that sort of mistake in the Morrison. I'm not saying that the situations are identical but it could be that we are misinterpreting the data and should be aware/cautious of that going forward.Anonymoushttps://www.blogger.com/profile/11914892485880621750noreply@blogger.comtag:blogger.com,1999:blog-4071831961528467035.post-33201477970852762712016-12-25T13:45:09.210-08:002016-12-25T13:45:09.210-08:00I have two issues with your arguments. The first ...I have two issues with your arguments. The first is that I don't see why basing diagnostic characters on referred specimens "should give one cause for consideration" if you can refer the specimens to the same taxon based on other apomorphies. Ceratosaurus DID have fluting on anterior teeth as shown by the dentisulcatus specimen. Maybe not all individuals did, but if we held to this level of uncertainty for all Mesozoic dinosaurs (most of which are only known from one specimen), our diagnoses wouldn't get far at all.<br /><br />The second issue is you give consistently present caveats far too much consideration. Most any character will be convergently developed by some other tetrapod, but that doesn't make them less valuable as part of a diagnosis. And when assigning a specimen to a taxon, you don't do it in a vacuum, so that e.g. phytosaurs' fluted teeth aren't a consideration at all because they were extinct by the Late Jurassic. Until you find a fluted example that matches Ceratosaurus' age, size and other anatomical characters, but is not Ceratosaurus, then it's perfectly fine to refer isolated Morrison fluted teeth to the genus. Similarly, the fact we don't know if every other coexisting taxon lacked a character doesn't mean we can't refer based on that character. It would be different if a relative of a Morrison taxon had the character, and the state was unknown for the Morrison taxon. Then you might say that Morrison taxon could also be a contender for owning the isolated fluted teeth, but that's not the case for Ceratosaurus' contemporaries AFAIK. Again, if we held this standard to every taxon, we wouldn't get far at all with diagnoses. This is especially true when we consider basically all Mesozoic ecosystems are only known by a fraction of their probable actual diversity, so that basically every Mesozoic dinosaur had contemporaries whose anatomy is completely unknown and so could have technically had any character state. But that would be a ridiculous reason to not refer material.<br /><br />In short, vert paleo is a provisional field, where it's perfectly fine to say Ceratosaurus is diagnosed in part by mesially fluted anterior teeth, without having to consider the caveats that are true of any character that maybe future finds of individuals lacking the character or of non-Ceratosaurus taxa with the character will falsify this, or that other distantly related taxa also have the character. Those are just givens.Mickey Mortimerhttps://www.blogger.com/profile/08831823442911513851noreply@blogger.comtag:blogger.com,1999:blog-4071831961528467035.post-92003925789492136462016-01-29T15:21:57.092-08:002016-01-29T15:21:57.092-08:00I agree with both your points. I absolutely agree ...I agree with both your points. I absolutely agree that we need to keep doing comparisons but, well...I'll get more into that in Part 2. I am sure you'll have comments there!<br /><br />Something is up indeed. I'll be talking in more detail about stechowi/sulcatus/etc., and touching on exactly those points. Anonymoushttps://www.blogger.com/profile/11914892485880621750noreply@blogger.comtag:blogger.com,1999:blog-4071831961528467035.post-22058370753836122592016-01-29T01:11:07.683-08:002016-01-29T01:11:07.683-08:00"Until they're published though, what can..."Until they're published though, what can we do?"<br />Good old-fashioned comparison. This is why I don't like the so-called "apomorphy-based approach" to identifying taxa, as exemplified by Nesbitt et al.'s (2007) review of Triassic North American dinosaurs. Proposed apomorphies provide only a fraction of the evidence we have available.<br /><br />"To me, saying that they were referred without much cause and then mentioning the lack of synapomorphies for Ceratosaurus with these remains in their Tendaguru ceratosaur section is in fact excluding these remains from Ceratosaurus."<br />Well yes, for ingens and roechlingi. I was thinking of the stechowi/Ostafrikasaurus teeth when I wrote that. Interestingly, these share Ceratosaurus' grooves but are not that labiolingually compressed, whereas the other diagnostic supposed ceratosaurid (Genyodectes) has great compression but no grooves. So something's up...Mickey Mortimerhttps://www.blogger.com/profile/08831823442911513851noreply@blogger.comtag:blogger.com,1999:blog-4071831961528467035.post-3081293493265389012016-01-28T08:25:35.523-08:002016-01-28T08:25:35.523-08:00Hi Mickey,
Thanks for the clarification on the Ten...Hi Mickey,<br />Thanks for the clarification on the Tendaguru specimens on display in Berlin. Since the display labels all said either Allosaurus or Allosauridae I assumed they all pertained to the same taxon and didn't double-check the specimen numbers.<br />You are correct that Carrano and Sampson do use Ceratosaurus sp. or Ceratosaurus cf. nasicornis. Obviously Mateus and his colleagues would dispute my assertion that later workers don't discuss non-NA occurrences since they have published a fair bit on material from Portugal. I'll have to post something later about that. Considering that Carrano and Sampson directly reference their work for the Portuguese specimens I can't really explain why I neglected to talk about it here. Maybe I'll make that Part 3.<br />Thanks for pointing out my misspelling in Rauhut's name - got it corrected now, thanks! And I definitely look forward to seeing the published version whenever you get a chance to send it.<br />Re: autapomorphies. I think you're right there, absolutely. It still leaves us with sort of a gap, though, until someone does a thorough specimen-level rigorous analysis looking for more. I am certain that more autapomorphies exist for this taxon (and many others as well). Until they're published though, what can we do?<br />Carrano and Sampson do imply that the Tendaguru remains should be excluded from the genus. On p. 185 (p. 4 of the PDF) the say, "Very few additional taxa have been referred to Ceratosauria sensu Marsh, 1884b. Among these were the fragmentary materials described as Ceratosaurus (?) roechlingi (Kimmeridgian-Tithonian, Tendaguru Beds, Tanzania:<br />Janensch 1925) and Chienkosaurus ceratosauroides (Tithonian, Kyangyuan Series, China: Young 1942). Other poorly known species (e.g. Megalosaurus ingens: Janensch 1920) have also been referred to the genus Ceratosaurus, but without much cause." Later they state in their section on Tendaguru ceratosaurs, " Although there are no apparent synapomorphies to support referral of this taxon to Ceratosaurus,the general morphology of the preserved elements does indicate an animal of similar phylogenetic status." To me, saying that they were referred without much cause and then mentioning the lack of synapomorphies for Ceratosaurus with these remains in their Tendaguru ceratosaur section is in fact excluding these remains from Ceratosaurus.<br />Hope to have Part 2 up this weekend or early next week.Anonymoushttps://www.blogger.com/profile/11914892485880621750noreply@blogger.comtag:blogger.com,1999:blog-4071831961528467035.post-64415152258803028062016-01-28T00:41:05.068-08:002016-01-28T00:41:05.068-08:00Ironically, I'm revising the Ceratosaurus entr...Ironically, I'm revising the Ceratosaurus entry in the Database this week. A couple comments... <br />I don't think "Allosaurus" tendagurensis has ever been suggested to be a carcharodontosaurid. Only the tibia in your photos is assigned to that species. The tooth on the left is the holotype of "Megalosaurus" ingens, while I bet the one on the right is a referred specimen of that species. The vertebra is MB R 1940, considered by Rauhut (2011) to be Theropoda indet. and possibly referrable to Veterupristisaurus. <br />Why do you say later workers "don't discuss any non-North American Ceratosaurus sp. remains"? There's been plenty of talk about the Portuguese stuff, and Carrano and Sampson (2008) discuss the Tendaguru stuff on page 27, even if we're waiting till next time for Rauhut (2011).<br />Yes, Britt et al. and Madsen and Welles were both talking about BYUVP 12893.<br />Rauhut (2000) listed all of those characters near verbatim in his thesis, but left out the serration one. The published version (2003) leaves out the premaxillary tooth number and chevron length characters too. I'll send you the thesis, and be sure to add the first 'u' to his name in the post.<br />"Of course you may notice that this list is pretty small, meaning that most of the skeleton can't be used to identify individual bones." Well, I'd say more that once some authors list a few obvious autapomorphies for a taxon, they don't bother looking for more.<br />"Carrano and Sampson (2008) ... restrict the use of Ceratosaurus to North America." Incorrect- they assign the Portuguese material to C. cf. nasicornis or C. sp.. It's true they don't mention Tendaguru teeth or meriani, but they also don't specifically exclude these remains from the genus.<br />Anyway, good post and I look forward to part 2.Mickey Mortimerhttps://www.blogger.com/profile/08831823442911513851noreply@blogger.comtag:blogger.com,1999:blog-4071831961528467035.post-20301543478083601902016-01-22T11:04:51.719-08:002016-01-22T11:04:51.719-08:00Excellent, I look forward to that! I've got a ...Excellent, I look forward to that! I've got a blog post coming out next week musing about Ceratosaurus teeth and what we actually know about them based on the published record. I hope you find it interesting.<br />-RobAnonymoushttps://www.blogger.com/profile/11914892485880621750noreply@blogger.comtag:blogger.com,1999:blog-4071831961528467035.post-50005981449320434332016-01-22T11:02:06.262-08:002016-01-22T11:02:06.262-08:00It is very true that we're often limited in sp...It is very true that we're often limited in space with our publications, especially in print venues.<br />I was actually going to delve into that megalosaurid paper this weekend, so I'm glad to hear that it covers exactly what I am looking for! I'll get into the 2014 paper you mention as well then too. Thanks for the heads-up!Anonymoushttps://www.blogger.com/profile/11914892485880621750noreply@blogger.comtag:blogger.com,1999:blog-4071831961528467035.post-81225414245988047942016-01-21T02:31:42.872-08:002016-01-21T02:31:42.872-08:00And I also wish to give a thorough description of ...And I also wish to give a thorough description of the Allosaurus and Ceratosaurus dentition in a far future, if possible! C. Anonymoushttps://www.blogger.com/profile/16241817488461509041noreply@blogger.comtag:blogger.com,1999:blog-4071831961528467035.post-11112092454996402212016-01-21T02:30:07.329-08:002016-01-21T02:30:07.329-08:00Many thanks for your post mostly referring to my w...Many thanks for your post mostly referring to my work on this terminology I recently proposed for theropod teeth, appreciated. One little comment though: "My biggest complaint is that the authors did not examine what a theropod tooth is. They identify problems with past work, the utility of teeth, and the need for a framework but there is no way to determine if this framework is applicable to a given tooth." Well, I already published two papers providing tools to identify isolated theropod teeth (Hendrickx & Mateus, 2014, Zootaxa, on abelisaurid teeth from Portugal and Hendrickx et al., 2015, Acta Palaeontologica Polonica, on the megalosaurid dentition) and a monograph sized paper on the distribution of dental features in non-avian theropod is on its way to be published in Palaeontologia Electronica. The latter discuss the taxonomic potential of isolated theropod teeth in relatively good details. Sometimes, one cannot add all the information he/she wants in a single paper, especially in a JVP paper!! Cheers, ChristopheAnonymoushttps://www.blogger.com/profile/16241817488461509041noreply@blogger.comtag:blogger.com,1999:blog-4071831961528467035.post-61163884941646787852016-01-20T05:25:22.719-08:002016-01-20T05:25:22.719-08:00I was surprised at the quantity and quality of ani...I was surprised at the quantity and quality of animal sounds that can be found on YouTube. The internet can be a wonderful resource.Anonymoushttps://www.blogger.com/profile/11914892485880621750noreply@blogger.comtag:blogger.com,1999:blog-4071831961528467035.post-47632267005682145782016-01-20T05:23:15.491-08:002016-01-20T05:23:15.491-08:00It varies, depending on what sort of job you are l...It varies, depending on what sort of job you are looking at. If you are looking at becoming a university researcher you are going to need a PhD. In the past people would get a bachelor's degree (four years), then a master's (usually two years), and then finally a PhD (several years - 2-7 depending on program specifics). A lot of schooling after leaving high school! Now some places are offering PhD-track programs to folks who have just completed their undergraduate degree, so you can get a PhD at a younger age.<br />Having said all that, there are more PhDs produced each year than available jobs. The job market for paleontologists is extremely tight.<br />Instead of going into academic research your son could go into contract paleontology. This is a great job, doing fieldwork to make sure power lines, roads, and pipelines are not damaging any fossil resources. Private companies, especially in California, also use contract paleontology firms to deal with specimens found during construction of buildings. Most contract jobs require just a master's degree.<br />As to what courses? Most paleontologists major in either geology or biology in their undergrad days. Obviously lots of those classes are handy. Statistics and other math classes will also generally be required - most science degrees require at least undergraduate calculus. Not being the best at math is not a death sentence for being a paleontologist, however, but you should go in with open eyes. If you struggle with math you will have to work twice as hard to make the grade in degree-required courses.Anonymoushttps://www.blogger.com/profile/11914892485880621750noreply@blogger.comtag:blogger.com,1999:blog-4071831961528467035.post-53507671322827407292016-01-13T06:03:22.652-08:002016-01-13T06:03:22.652-08:00Hopefully we'll get one when this assemblage i...Hopefully we'll get one when this assemblage is finally published. When that will be, however...?Anonymoushttps://www.blogger.com/profile/11914892485880621750noreply@blogger.comtag:blogger.com,1999:blog-4071831961528467035.post-22817622250945797982015-12-22T08:06:22.393-08:002015-12-22T08:06:22.393-08:00My son is in 5th grade and he want to be a Paleont...My son is in 5th grade and he want to be a Paleontologists when he grows up. He was wondering how long you had to go to school for it and what type of classes you need to take. Thank you!Anonymoushttps://www.blogger.com/profile/11859308022950106654noreply@blogger.comtag:blogger.com,1999:blog-4071831961528467035.post-9483416353936006922015-10-30T13:02:34.464-07:002015-10-30T13:02:34.464-07:00This is fascinating! I've been exploring YouTu...This is fascinating! I've been exploring YouTube since, exploring different bird and crocodile sounds.Jake Kalehttps://www.blogger.com/profile/00951963971909024869noreply@blogger.comtag:blogger.com,1999:blog-4071831961528467035.post-44370500711146107132015-10-24T17:42:51.374-07:002015-10-24T17:42:51.374-07:00I agree that the faunal evidence does not necessar...I agree that the faunal evidence does not necessarily support a Late Triassic age. In fact it seems more likely that drepanosaurs survived into the Jurassic. Need a good U -PB date.Bill Parkerhttps://www.blogger.com/profile/05941940882532354219noreply@blogger.comtag:blogger.com,1999:blog-4071831961528467035.post-28343027218197509122015-09-13T13:51:53.414-07:002015-09-13T13:51:53.414-07:00Thanks so much!!Thanks so much!!Thomas Holtzhttps://www.blogger.com/profile/05580730835586277579noreply@blogger.com